Review on Optimize Your Mixing Ratios with Custom Shop's Calibrated Solutions by Joel Young

Unfortunately they are not worth the money. First of all, I only got ten cups instead of twelve, and two of the ten were cracked, so unusable. When trying to remove the cup from the stack, the rim of the cup broke off, so these cups are not very strong. Thin plastic and somewhat fragile. I can't imagine what would happen if you had to apply pressure when mixing something viscous like silicone etc. The dimensions printed on the mug may be helpful. I will not buy these again.